H4 visa renewal--DS 160 FORM --Everybody pls help

[immihelp]

1. Yes, till that date in 2011.

2. Read https://www.immihelp.com/us-visa-app...n-form-ds-160/

3. Yes

[invisible]

I Was filling for my H4 visa renewal stamping in India, Hyderabad, iam not understanding some fields as what to enter as below:

1) Intended Length of Stay in U.S. (Iam on h4 and I dont understand as
how many days I need to specify, My I 797/h4 extnsion is valid till
jan 2011)

2)Previous U.S. Visas : Visa Number (I don't understand what is this
visa number)

3)Have you ever been issued a U.S. Visa?
Yes / No ? (I have H4 lived in the US for 1 yr 9 months but now in india on vacation since 5months)